Concrete Repair

Concrete repair starts with the cause. Surface scaling is thin flakes coming off the top. The National Research Council's digest on concrete in winter calls it "perhaps the most easily recognized result of frost damage" and says it occurs mainly on pavements, sidewalks and other horizontal surfaces, and is most severe where de-icing salts have been used. The same digest says that freezing of concrete in the plastic state "usually results in permanent damage, even with a single cycle".

Heaving and settling point below the slab. Clays, silts and very fine sands heave when they freeze, while sands and gravels do not, and the Building Code's appendix notes that clay soils expand and contract with moisture and that thirsty trees can dry them out. A slab that keeps moving may need its base fixed, not just its surface.

Steps are a special case: if a set of more than 2 risers has dropped, the 2024 Building Code expects that size of step to sit on walls or piers to foundation depth, or be cantilevered from the house foundation (Div. B, 9.8.9.2.). Foundation wall cracks are waterproofing work, not flatwork.

Ask for a written diagnosis first: what failed, the repair method and whether replacing the slab is the better answer. Since March 1, 2026 the City of Ottawa requires a hardscaping contractor licence for any business that installs or alters concrete pads, patios, walkways, steps, driveways or retaining walls on private property. Ask to see the licence and check the City's list of licensed hardscaping contractors yourself; we do not check it for you.

The Licensing By-law excludes "minor repairs or minor alterations" from the hardscaping licence and does not define "minor", so ask the City whether your job counts.